This project will continue the maintenance and updating of Online Mendelian Inheritance in Man (OMIM(r)), a unique curated knowledgebase of genetic disorders and genes that has been an essential resource for clinical geneticists and researchers in molecular biology, genetics, and genomics for nearly 50 years. OMIM is freely available on the website OMIM.org. The primary focus of OMIM is the delineation and description of the increasingly complex and nuanced relationships between human disorders and traits and the genes that underlie them. Updating of OMIM is based on expert review of the biomedical literature. Unlike databases of primary data, OMIM synthesizes and summarizes new and important information, which is entered in a structured format. The curation of the database, including classification of disease, the creation of new phenotype and gene entries, and updates to the over 22,300 existing entries, is performed by staff members who have extensive experience with OMIM and expertise in cataloging information that elucidates the genetic basis of disease. The OMIM entries and clinical synopses are mapped to structured language resources such as ICD9/10, SNOMED, HPO, and the UMLS. OMIM's gene map and morbid map provide a condensed view of the relationship between genes and disease. OMIM has a robust API to facilitate computational survey and integration of OMIM data. OMIM's stability and authority are internationally recognized, and MIM numbers are included in articles across many medical subspecialties. OMIM.org has thousands of daily users worldwide and this number is expected to increase as genomics becomes more integral to all fields of medicine. OMIM leverages data from other resources to enhance its unique content and collaborates with other informatics resources and curation efforts to provide user-friendly access to medical genomic information. OMIM will continue to operate in a cost-effective manner with the support of an expert scientific advisory board and consultations with its growing user base. With an unparalleled breadth and richness of description of human phenotypes and genes, OMIM will continue to provide authoritative and timely support to clinicians and researchers.